Snow And Ice Ebook
Intrasedimental ice develops where water freezes or water vapour sublimates within soil, sediment or bedrock. It develops in proglacial permafrost in two situations (1) where pressurized glacial meltwater freezes onto the base of the permafrost or is injected up into it or (2) where permafrost re-aggrades through sediments that are subglacially thawed by the insulating effects of a thick body of glacier ice, and then, following glacier retreat, subaerially frozen upon re-exposure to cold winter air temperatures. In both cases, the overall effect of the glacier or ice sheet, except where the ice is predominantly cold-based or where its substrate has a very low permeability, is to predispose the permafrost to becoming ice-rich (i.e., where the ice volume exceeds the pore volume of the ground in an unfrozen state). Besides pore ice (ice cement), the most important types of proglacial intrasedimental ice, in terms of glacier-permafrost interactions, are segregated ice and intrusive ice....
It is occasionally said that Britain and Ireland owe their mild climate to the presence of the Gulf Stream and the North Atlantic Drift. Thus, the story goes, the Gulf Stream brings warm water from Florida up the eastern seaboard of the United States and then across the Atlantic in the North Atlantic Drift to the shores of Britain and Ireland, hence moderating the otherwise cold winters. Certainly, the surface temperature of the eastern North Atlantic is a few degrees warmer than the water at the same latitude off the coast of Newfoundland, as figure 2.2 in chapter 2 illustrates. Although this difference does have some effect on the temperature differences between the two locations, Britain and Ireland have a moderate winter climate primarily as a consequence of the fact that they are next to the ocean, with the ocean on their west. Even if there were no gyres in the ocean at all, the climate of these parts would be much more moderate than the climate at similar latitudes on the...
A careful thermal analysis is necessary for all systems located where sub-freezing temperatures occur during the winter months. This is to ensure adequate performance via the temperature-sensitive nitrogen and BOD removal responses and to determine if restrictive freezing will occur in extremely cold climates. A
A band of tundra existed just south of the major ice sheets in North America and Eurasia, at least during the last glaciation, and probably also during previous glacial periods of the Pleistocene. The ice sheets themselves helped create the sort of chilled climatic conditions that favor tundra vegetation. Bitterly cold winds flowed off the ice sheets, creating cold regional climates. When the ice sheets reached their maximum extent during the last glaciation, their outer margins were in the midlatitudes (45-50 N), so during such times, Arctic tundra communities existed much farther south than at any other time.
Proper control of the ventilation system is important to the maintenance of aerobic conditions at all times and to the minimization of heat loss during cold weather operation. As discussed in Section 19.2.4, the openings on natural draft ventilation systems must be reduced during cold weather operation to reduce airflow and the resulting heat loss. In contrast, openings must be increased as much as possible during more temperate conditions to encourage adequate air-flow.
Some scientists have argued that global warming might have an effect on the North Atlantic Current. As Arctic glaciers melt, freshwater may be dumped into the current. As discussed earlier, both temperature and salt-water content have an impact on currents a giant dump of cold, freshwater could therefore have an effect on how a current flows. The worry is that the current could rapidly collapse, turning off the huge heat pump and altering the climate over much of the Northern Hemisphere. 19 Some scientists have suggested that the result could be a new ice age. Even if the North Atlantic Current is affected, however, it is far from clear that the result would be a new ice age. In fact, according to Richard Seager, a climate researcher at Columbia University, Europe's mild climate is not primarily a result of the North Atlantic Current. Instead, in an article in American Scientist in August 2006, Seager explained that Europe has mild weather mostly because it has a maritime climate...
Strikes, and then later by learning how to create it at will. Control of fire brought greater protection against cold weather and wild animals, the ability to render raw meat more edible, and the possibility of manipulating the landscape by intentionally burning to improve prospects for game, in effect an early form of wildlife management.
Mars has no ocean, little thermal inertia, and a thin atmosphere that has a relatively modest effect on the planet's surface temperature. These features should lead to a different, and perhaps simpler, response to orbital forcing on Mars as compared to Earth. The predicted climate changes have been simulated in detail using comprehensive climate models, but we will confine ourselves here to some general remarks. The main effect of Martian Milankovic cycles is likely to be the redistribution of water deposits, in the form of either glaciers or permafrost. There are two aspects to this redistribution. On the short precessional time scale, the asymmetry between the Northern and Southern polar ice caps should reverse. For example, about 25000 years ago, the Southern hemisphere should have had milder summers and winters, while the Northern had cold winters and hot summers the default reasoning would imply that at such times, the Southern ice cap should be large and be composed mainly of...
According to the Koppen (Parker, 1972) climate classification system, the most typical climate in the USSR is humid continental, marked by at least some (but sometimes not much) precipitation all year round but with cool summers and cold winters. This type of climate is characteristic for 31 percent of the USSR. By way of comparison, this same type of climate can be found only in small parts of Alaska in the USA. The most typical climate in the USA is humid temperate, characterized by rain all year round with hot summers and mild winters. This type of climate is characteristic for 34 percent of the land area in the USA, but is found in only 0.5 percent of the USSR in an area along the Black Sea coast (Parker, 1972).
The significance of a need for redefinition can be underlined by overall changes in the patterns of death rates from extreme climate events. US death percentages (CSCCC 2007) lean increasingly away from major disaster events towards thermal or first order extremes. In percentages terms for the period 1992-2002, thermoregulatory deaths accounted for 82 of the total 1275 annum extreme cold 53 , heat 28 , flood 9 , lightning 5 , tornado hurricane 5 . Since reductions in death rates is largely a matter of economic development and research and investment, a more sophisticated understanding of first order thermoregulatory processes may have the potential for relatively large net returns.
When Earth's tilt changes, the seasonal distribution of insolation at the higher (polar) latitudes and the length of long, cold winter periods at the poles also change. Changes in tilt do not have much effect on the equatorial regions. The higher the degree of tilt, the more pronounced are the seasons. The more extreme the winters are at the poles (longer and colder), the more likely ice sheets are to grow. ellipse, which varies from 1 to 5 percent. With a periodicity rate of approximately 100,000 years, it affects the amount of radiation Earth's surface receives at aphelion and perihelion. Aphelion is the point on its orbit where Earth is farthest from the Sun perihelion is the point where it is the closest. This cycle changes the seasonal contrasts in the Northern and Southern Hemispheres. When the orbit is very elliptical (oval shaped), one hemisphere will have hot summers and cold winters and the other hemisphere will have warm summers and cool winters. When the orbit is more...
Hotter temperature extremes and more frequent, more intense, and longer-lasting heat waves are robust projections of the models examined by the IPCC, portending increased heat-related illness and mortality. Growing seasons will also become longer because of earlier spring warming and later fall cooling, but crops will face greater heat stress and associated drought during the growing season. Cold spells will become less frequent, causing fewer deaths and economic losses associated with cold weather.
The global warming exaggerations that Lomborg supposedly uncovered in chapter 3, which he titled Global Warming Our Many Worries, were listed in the chapter as follows Melting Glaciers, Rising Sea Levels, Penguins in Danger Extreme Weather, Extreme Hype, Flooding Rivers, A New Ice Age over Europe, Malaria in Vermont, More Heat Means More Starvation, and Water Shortages. The first two of these issues melting glaciers and rising sea levels will be examined in this chapter. Most others will be examined in subsequent chapters. Melting Glaciers Currently, ice permanently covers 10 of the land surface, with only a tiny fraction occurring outside Antarctica and Greenland. Ice also covers approximately 7 of the oceans in the annual mean. In midwinter, snow covers approximately 49 of the land surface in the NH Northern Hemisphere . An important property of snow and ice is its high surface albedo the fraction of solar radiation reflected by the Earth's surface, expressed as a percentage4 ....
In the ablation area there may be a surface layer of cold ice, several meters in thickness, in which the veins are frozen. This cold layer forms on glaciers in more continental climates where snow fall is low enough to allow appreciable cooling of the ice by conduction during the winter (Hooke et al., 1983). It is less likely to form in maritime climates where larger snow falls form an effective insulating layer. When present, it is likely to persist well into the melt season, if not entirely through it, and thus forms an effective barrier to penetration of surface meltwater. Because of this cold layer, and because the vein system, even on glaciers without such a cold layer, is relatively ineffective in transmitting water downward, it is, again, principally by way of crevasses that surface water in the ablation area is able to reach the interior of the glacier.
In pristine waters, total phosphorus (TP) concentrations are around a few micrograms to a few tens of micrograms per liter, while total nitrogen (TN) concentrations will usually be ca. 10-20 times as high. Since P compounds are less soluble than nitrogen, P is usually scarce in aquatic systems and frequently limits algal growth. However, the sediments in shallow systems experience relatively high temperatures in summer. This leads to an increase in mineralization rates and higher release of nutrients from the sediment when the supply of organic matter is very high. These processes may enhance the eutrophication effects in shallow lakes. Much of the P that has been trapped in the sediments during periods of high loading or, in the temperate zone, during cold winters can be easily released to the water column, a process called 'internal loading.' This phenomenon is frequent in shallow eutrophic lakes even after the external loading has been reduced (due to improved wastewater treatment,...
A distinctive characteristic of the Arctic atmosphere is the surface weather systems associated with a large-scale, cold-cored westerly circumpolar circulation in the middle and upper atmosphere (see Polar Vortex). Cyclones (low atmospheric pressure areas) and anticyclones (high pressure) are embedded in and steered by this flow, and variability in the path of these can radically affect the weather and climate beneath the vortex.
The Antarctic subglacial environment may be similar to the environment beneath the widespread ice sheets in the Neoproterozoic, a time period from about 750 to 543 million years ago. It has been suggested that during this period the Earth experienced a number of massive glaciations - covering much of the planet for approximately 10 million years at a time. The evidence for an ancient ice covered planet comes from thick widespread sedimentary sequences deposited at the base of large ice bodies. These glacial units alternate with thick carbonate units - warm, shallow-water sedimentary deposits. These paired sequences have been interpreted as representing a long period when the Earth alternated between an extremely cold, completely ice-covered planet (the snowball Earth) and a hothouse planet. Some speculate that the extremes of these climates introduced an intense environmental filter , possibly linked to a metazoan radiation prior to the final glaciation and an Ediacaran radiation....
Subsequently, improvements in technology enabled people to survive in cooler regions. They learned to make clothing to keep them warm and to build houses to retain the heat. Glass was invented and made windows possible. The Romans invented the hypercaust that enabled them to keep their homes warm in cold weather. Civilization then spread northwards with the help of Roman technology. Around the end of the first millennium AD improvements in agriculture further aided the spread of civilization. The stirrup and the horse collar enabled the horse to replace oxen for ploughing, and together with the wheeled plough that turned the soil over enabled the heavy fertile soils of Northern Europe to be opened up for cultivation. This in turn enabled the land to support a much greater population than ever before.
The compilation of composite trans-Atlantic hydrographic sections presented in Figs. 24.2 and 24.3 introduces all principal water masses of the subpolar North Atlantic evolving from their warmest and saltiest state of the mid-to-late 1960s to the extremely cold and fresh phase of 1994 and then to the generally warmer and saltier conditions of the recent years. The differences between the two extreme states have been thoroughly analyzed in several recent publications (Yashayaev 2007a, b Yashayaev et al. 2007a Boessenkool et al. 2006). Here we review and expand those analyses by considering two other trans-Atlantic sections (2001 shown in Figs. 24.2c and 24.3c, and 1962 shown in Fig. 24.14) and by discussing temperature changes.
Grain sorghum (Sorghum bicolor), a native of the African continent, is grown extensively in the southern Great Plains as a seed crop for animal feed. It is weakly perennial in tropical regions, but is killed by frost at higher latitudes. Johnsongrass (Sorghum halepense), a weedy relative of cultivated sorghum, is in the U.S. a troublesome weed that overwinters by production of rhizomes, fleshy underground stems capable of winter survival. It may be feasible to convert a tetraploid variety of grain sorghum from an annual to a perennial growth habit by combining in hybrids good grain quality with the ability to produce winter-hardy rhizomes (Piper and Kulakow, 1994). The ease of making this transfer will depend on the number of genes controlling the production of rhizomes and whether or not overwintering ability is genetically associated with poor agronomic characteristics.
The presence of fungi was least investigated in polar glaciers. Filamentous fungi and yeasts were found in the microbial cryoconite holes that probably serve as biological refuges during extreme cold Margesin et al., 2002 Reeve et al., 2002 . Viable filamentous fungi and yeasts have been isolated from 10,000-13,000 years old Greenland ice Ma et al., 1999, 2000 , 12,000 years old Antarctic Vostok ice core sections Christner et al., 2000, 2002 , and even from Antarctic ice layers up to 38,600 years old Abyzov, 1993 . In all these cases the isolated fungi were filamentous and their numbers were low, while viable yeasts of the genera Cryptococcus and Rhodotorula have been found only in the upper, younger ice-sheet horizons and surface layers of ice and snow. The oldest yeasts were isolated from horizons 700-3,250 years old Abyzov, 1993 .
Central Yukon has a sub-Arctic continental climate with long, bitterly cold winters, short mild summers, low relative humidity, and low to moderate precipitation (Table 3). Intrusions of mild air from the Pacific Ocean moderate the climate of the region from the Arctic climate that characterizes northern Yukon 77 . The Dawson Range shares this climate modified by higher elevations. However, higher elevations do not necessarily experience colder temperatures throughout the year. Air temperature decreases with increasing elevation during the summer months but, during the winter, cold air is frequently trapped within the Yukon River Valley and other major valleys causing a temperature inversion 77 . The Dawson Range has a periglacial climate. It is situated within a region of Yukon classified as having extensive discontinuous permafrost 19 . However, the summits of the Dawson Range lie below the regional firn line.
The optimal time for construction also has to be determined. Preferably exposure of frozen soils is to be done during winter. This limits the thermal disturbance caused by the construction activity. In fact, by exposing the foundation to the cold winter temperatures and placing insulation at the end of the winter, initial foundation temperatures can be obtained that are colder than average. In addition, access on frozen terrain is easier than on thawed ground. However, winter construction is tougher on the machinery and workers due to climatic conditions (cold temperatures, snow), the period of sunlight is much shorter, and the construction site or the access route may be located in avalanche zones.
The Koppen Climate Classification System has been refined to account for subtler variations in climates. A third letter is applied to denote these sub-zones. The lowercase letter a is used to indicate hot summers where the summertime temperatures are above 72 degrees F (22 degrees C) in the warmest month. Zones C and D are climates where these conditions prevail. The lowercase letter b is used to indicate areas where there are warm summers with the warmest month below 72 degrees F (22 degrees C). Again, these conditions are found in Zone C and D climates. Lowercase c is used to indicate areas with cool, short summers. In these areas, the summertime lasts less than four months. The temperatures reach over 50 degrees F (10 degrees C). Zone C and D climates have areas with these conditions. Areas with a d designation have very cold winters, with the coldest month having temperatures that reach below minus 36 degrees F (minus 38 degrees C). Areas with these conditions are found in the D...
Temperature is another factor whose impact on trickling filter performance has historically been poorly understood. Ample full-scale evidence exists demonstrating that the performance of a trickling filter can decline significantly during periods of cold weather Based on such observations, it was concluded long ago that the trickling filter process is relatively temperature sensitive. With an improved understanding of biofilm processes, however, it was realized that, in many instances, substrate removal is controlled more by mass transfer than by biological reaction.1 Moreover, since temperature effects on mass transfer are often modest, the effect of temperature on trickling filter performance should also be relatively modest. Further analysis suggests that the observed significant effect of cold weather operation on trickling filter performance is often a result of severe temperature drops due to the physical configuration of the system. When such drops occur, the biological...
The directional angle that Earth's rotational axis tilts defines, in part, these extreme cold periods and the relatively warm periods the planet experiences. The rare warm period currently being experienced has led to the rise of human civilization on Earth. The complex interaction of orbital variations, solar intensity, and the unprecedented increase in greenhouse gas concentrations in the atmosphere is yet to be fully understood. While humanity cannot control celestial mechanics, it can modify its own behavior when it comes to greenhouse gases emissions.
The switch from coal to oil was complete by the 1960s, with the vast majority of Americans heating their homes with oil. It was just about the same time that the nation, and much of the world, suffered through the coldest decade of the 20th century. Little-discussed today, the winters of the 1960s were so severe that some people, including scientists, spoke of a coming ice age (those discussions were renewed during the brutally cold winters of 1978, 1979, 1982, and 1983). Americans did not feel the pinch during the 1960s because gas and home heating oil remained at roughly the same low prices during that decade, but their European counterparts saw the prices of the same commodities double in the 1960s. By 1970, Europeans were making smaller, more fuel-efficient automobiles, while the American auto industry continued to go for size and impressive performance on the highway.
A natural cooling trend in the Northern Hemisphere should have passed the threshold for initiating a new glaciation several thousand years ago, but greenhouse gases added by humans kept climate warm enough to avoid the start of a new ice age. 10.3. A natural cooling trend in the Northern Hemisphere should have passed the threshold for initiating a new glaciation several thousand years ago, but greenhouse gases added by humans kept climate warm enough to avoid the start of a new ice age. Still, the model gives an indication of whether or not ice is likely to have formed in any particular region. It simulates the thickness of snow cover (and sea ice) throughout the year, balancing the accumulation of snow and ice in autumn and winter against the melting in spring and summer. The critical issue is whether or not any snow cover or sea ice persists through the entire summer. If it does, the next winter's snow can add to the thickness, and then the next and the next. In time these...
For example, all of the Laurentian Great Lakes were invaded by alewife. which became the primary forage base for salmonids (Christie 1974). Alewife populations cycle explosively, but may be undergoing a long-term decline due to overstocking of salmonids, a series of cold winters and other factors. In Lake Michigan, effects of the alewife decline are compensated by expansion of the native club populations. Lake Ontario, in contrast, has lost its native club populations and a sustained alewife decline could lead to collapse of the fishery.
The length of the Greenland right whale varies between 12 and 18 m although a whale can reach lengths of 20 m, only a few exceed 18 m. At birth, the length is about 4 m. In general, females are longer than males. After the feeding season the animal has a layer of blubber approximately 60 cm thick, which helps protect against extreme cold, and the average weight of an adult whale is about 75-100 metric tons. The body coloration is black, but there is a white spot on its chin on the lower jaw, and a light spot on the tail and or fluke plates. The skin is smooth. The throat, chest, and belly lack ventral grooves and the back is smooth with no dorsal fin or ridge as other related species have.
The climate in Asia varies between extremes of both temperature and precipitation. It is governed by the monsoon winds and influenced by the high mountain ranges. After the temperatures start soaring during the summer (April onwards), the southwest monsoon brings very large amounts of precipitation over the south and southeast Asia. The large mountain ranges influence the spatial distribution of rainfall, resulting in sharp gradients. During winter, monsoons from the north move into East Asia and cause cold dry weather. Bitter cold polar winds keep part of northern Siberia frozen throughout the year. More than one-third of the Asian continent is therefore arid (annual precipitation
Good maintenance of a vehicle battery can prolong a battery's life and for this the following procedures can be followed (a) Check the battery for adequate water level if the battery is not a sealed one, and check the battery and the vehicle charge system to determine whether the battery is low on water. (b) Do not overfill a battery. (c) Make sure all the connections are clean. (d) If the vehicle has been seldom used, charge the battery at least every 2 months to maintain the battery charge, because in a discharge state, the battery might freeze. (e) If the battery must be stored outside of the vehicle, store it in a cool dry place. (f) Do not jump start a battery when the battery is extremely cold. (g) When jump starting, connect the jumper cables first to the power source, then connect the positive cable to the positive cable on the battery to be jumped and the negative to a solid ground on the vehicle (e.g., the bracket on the alternator). This avoids electricity going directly to...
The mechanism is thought to involve the sort of change in the distribution of Atlantic winter storm activity that has long been associated with opposite extreme states of the NAO (Rogers, 1990). From the late 1950s to 1970, under the more-southerly of its two main cells, a regime of cold winter air temperatures and extreme snowcover greatly enhanced the land-sea temperature gradient at the US eastern seaboard, spinning-up more storms than normal offshore (Dickson and Namias, 1976 Hayden, 1981) and causing them to develop more rapidly to occlusion in a narrow band following the main coastal baroclinic gradient. The local effect was to focus the centre of maximum storm activity off the US eastern seaboard where the cold, stormy conditions caused maximum formation and ventilation of the Eighteen-Degree Water pycnostad, and some increase in its density (Jenkins, 1982 Talley and Raymer, 1982 Talley, 1996b). The remote effect was to reduce stormi-ness over the Labrador Sea to a post-war...
Zonation is typified by the more or less latitudinal arrangement of Arctic terrestrial communities around the pole, as described above. It is also exemplified by the altitudinal distribution of biomes on mountains even lofty peaks at the equator have treeless tracts of vegetation at high enough altitudes. Altitudinal zona-tion on Arctic mountains is less pronounced than on mountains of temperate and tropical regions. Nevertheless, as one ascends there is a trend for the vegetation to become more sparse and reminiscent of polar desert. Extreme cold, high winds, and lack of moisture curtail life. Within glaciers and ice fields, mountains may protrude as nunataks. These can
The discharge of glacial streams is highly variable, depending on the season, time of day, and cloud cover. Maximum discharges occur during the afternoon on warm, sunny summer days, and minima on cold winter mornings. Beneath or within a glacier, the water flows in tunnels and is generally pressurized during periods of high discharge. In addition to debris washed in from unglaciated highlands adjacent to the glacier, a glacial stream can pick up large amounts of debris along its path at the base of the glacier. For this reason, meltwater streams issuing forth at the snout of a valley glacier or along the margin of an ice sheet are generally laden to transporting capacity with debris.
159-161, 170, 172, 174, 185, 187, 188, 191, 201, 223, 308, 310, 311, 375 Planet Earth, ix, xix, xv, xvi, xvii, xviii, 21, 33, 34, 73, 96, 104, 159, 186, 201, 202, 220, 241, 247, 332, 403-407, 409-412, 414, 415, 417-419, 427-429, 432, 459 Polar vortex, 203 Political management, 388 Pollution, xv, xvi, xviii, 23, 26, 33, 63, 160, 162, 170, 219, 222, 287, 288, 359, 360, 406, 441, 453, 458 Polyculture, 275, 279, 313, 361 Polyembryony, 323 Population dynamics, 57, 203, 328 Population genetic structure, 329 Postglacial rebound, 9 Post-harvest management, 257-262 Post-natural, 416 Pre-Christian, 403 Pre-industrial age, 13 Preservation of the species, 458 Primary production, 22, 117, 167, 170, 172,
For the past 600 yr (Fig. 21.7A) the hemispheric picture is dominated by temperatures below the mean of the reference series. A pronounced cold interval appears around ad 1450 and other prolonged cooler intervals are centred around ad 1600, 1700 and between ca. 1800 and 1900. How far does climate data from Iceland mimic this record The data from Stykkisholmur, northwest Iceland (Fig. 21.3), extends back to ad 1820. The winter (J, F, M) and summer (J, J, A) trends (Fig. 21.7C) indicate an interval of both cold winter and summer temperatures centred on ad 1860 followed by a rather dramatic increase in temperatures, led by winter values, starting ca. ad 1900. The correlation between winter and the subsequent summer temperatures is quite evident (r2 0.48) the correlation between the Mann et al. (1999) series and Stykkisholmur is only r2 0.14.
The first studies of the thermocline were motivated by Ellis' (1751) measurements that revealed extremely cold water at depth in the tropical Atlantic. Rumford (1800) speculated that cold currents from polar regions must sustain the low temperatures in low latitudes. Lenz (1845), who first noticed that the depth of the thermocline decreases with decreasing latitude in the tropics (see Fig. 4.4.1a), inferred that there is equatorial upwelling sustained by a pair of thermohaline cells, one in each hemisphere (see Warren, 1981b, for a historical review of this topic). A century later, these ideas are quantified (Robinson and Stommel, 1959 Robinson and Welander, 1963) in a model in which the thermocline depends on a balance between the downward diffusion of heat and the upwelling of cold water.
The expansion of the Antarctic polar vortex during the 1990s, both in spatial and temporal extent into early summer, has increased the frequency of elevated UV-B episodes over sub-Antarctic populated areas (Rousseaux et al., 1999). These episodes are no longer just small pockets of ozone depleted stratospheric air coming from the break-up of the polar vortex, but include occasional excursions of the polar vortex edge over Ushuaia, Argentina and Punta Arenas, Chile. This occurred 44 times in the years 1997, 1998, and 2000 combined, with some episodes lasting three to four days. Surface measurements show average erythemal UV increases of about 70 over Ushuaia (54.47 S) since 1997, and episodic total UV-B increases of up to 80 over Punta Arenas (53.08 S) (WMO, 2007). The measured amounts of UV irradiance at Palmer Station, Antarctica (64 S) and San Diego, CA (32 N), show that for all seasons, other than spring in Antarctica, there is a decrease in UV-B irradiance caused by the increased...
Throughout the year a mean westerly (zonal) flow dominates much of the middle latitudes of both hemispheres (Figs. 1A and 2A). The zonal flow is strongest in each hemisphere's winter and weaker in the summer. However, the zonal flow is strongest in both hemispheres in the southern winter (Fig. 2A), and the weakening occurring in the southern summer reaches an intensity that still approximately matches the mean strength of the flow during the northern winter (Fig. 1A). The mean flow during the northern summer is seasonally the weakest on the planet. Comparison between hemispheres in Figs. 1A and 2A also reveals a greater wavelike structure, or meridionality, to the flow in the Northern Hemisphere. Northern winters are occasionally beset by periods in which the westerly flow decreases or becomes blocked, and meridional (north-south) flow begins to dominate the circulation. This flow is accompanied by an amplification of the wave ridges, notably the ridge visible at higher latitudes over...
One would infer that systems with all growth forms represented should have higher rates of production than those missing some growth forms, all else being equal (particularly climate). However, we know of few available data to test this prediction. There is less conceptual basis (and even fewer data) to support the notion that the presence of more species within a growth form will lead to higher productivity. Cowling et al. (1994) pointed out that functional redundancy within growth forms, where several species responded similarly to climatic factors, was usually explained by the species having different responses to rare catastrophic droughts. Thus species richness would be predicted to minimize fluctuations in plant cover and production over time. Diversity of photosynthetic processes might also be expected to affect productivity. However, in one cold-winter semi-arid region, there was no substantial difference in carbon fixation or water use between communities dominated by shrubs...
In 1977, the decline in grain production in the USSR was certainly caused by poor weather, the main feature of which was the prevalence of unusual cold throughout the whole year with the single exception of autumn. The cold weather was associated with a very stable zone of high atmospheric pressure in the Polar region. In the high latitudes of Europe, east winds prevailed. The Arctic anticyclone spread over a vast territory to the east of the Urals and blocked cyclones moving from the west over European Russia. During the summer, in central regions of European Russia the weather was dominated by an influx of these numerous cyclones, bringing cold and rain. During the year, precipitation was excessive in most regions of European Russia. In July and August, in southern Ukraine, precipitation was 300 and 200 percent of the norm. These figures were the highest ever recorded for this area (Bulletin of WMO, 1978). The wet and cold weather affected crops in European Russia. In the non-black...
Glaciers form mainly by the accumulation and compaction of snow, and are deformed by flow under the influence of gravity. When snow falls it is porous, and with time the pore spaces close by precipitation and compaction. When snow first falls, it has a density of about 1 10th that of ice after a year or more the density is transitional between snow and ice, and it is called firn. After several years the ice reaches a density of 0.9 g cm3, and it flows under the force of gravity. At this point glaciers are considered to be metamorphic rocks, composed of the mineral ice.
Chemically perturbed region That region of the polar vortex containing air which has been exposed to PSCs and, in general, contains high abundances of CI,. of darkness every day. polar stratospheric clouds (PSCs) These clouds form in the cold temperatures of the lower stratosphere of the winter and early spring polar vortex. Type I PSCs form from the co-condensation of H20 and HN03, while type II PSCs form from the condensation of water vapor. Chemistry necessary for the formation of the ozone hole occurs on the surfaces of these clouds, polar vortex The air mass that is located poleward of the polar night jet. This region is cold (so allows the formation of PSCs) and isolated from mid-latitudes by the strong zonal winds of the polar night jet. potential temperature (theta) The temperature that the parcel would have if it were moved adiabatically to a reference pressure, usually the surface pressure (1000 hPa).
While high porosity and low thermal conductivity make snow a protective blanket against extreme cold, this same openness makes it quite permeable to flows of air and water. Snow acts as both a source and a transmitter of water, quickly routing it through to the ground, which then channels much of the water to streams or rivers. Knowledge of the snow melting rate and snow hydrological processes (Marsh, 1990 Bales and Harrington, 1995) allows a more accurate prediction of flooding and of the distribution of water for agriculture and forest growth. Possible increased rainfall and snowmelt as a result of global warming increase the urgency for accurate runoff predictions (Jones, 1996). As well as its hydrological significance, snow acts as a buffer to chemical species transported by wind, rain, and meltwater (Bales etal, 1989 Davis, 1991 Harrington and Bales, 1998).
If NATO warships had made their way through Russia's territorial sea and along the Northern Sea Route during the Cuban Missile Crisis in 1962, then the Kremlin could easily have assumed the worst. Perhaps the most extreme Cold War example of the consequences of such mistrust is the nuclear catastrophe that nearly took place in November 1983, when Soviet chiefs became convinced that NATO
Global Change Research Program, the warming projected by climate models over the next several decades suggests increases in rain episodes over frozen ground or rapid snow melting events that can increase flooding. Over the coming century, winter snowfalls and periods of extreme cold will probably decrease. Of major concern for this area are changes in the intensity and frequency of hurricanes.
Deciduous forests are a feature of mid-latitude climates with cold winters. Yet at still higher latitudes with even colder winters (as in much of Canada or Russia), evergreen conifers (mostly of the pine family, such as Pinus, Abies, and Picea) are dominant instead. This seems to contradict the explanation for temperate trees losing their leaves surely here the need to drop leaves in winter is even greater, and yet these are
Are also influencing stratospheric ozone depletion. In particular, greenhouse gases are expected to enhance radiative cooling of the lower stratosphere and increase stability of the Arctic polar vortex, creating conditions that will further aggravate ozone depletion 6,8 . Recovery from ozone depletion and elevated UV is likely to be slow over the next half century 9 .
In this process, high-purity oxygen is used in lieu of air as the oxygen source. The process is typically carried out in a closed tank similar to the activated sludge process for wastewater using pure oxygen. High-purity oxygen atmosphere is maintained in the space above the liquid surface, and oxygen is transferred into the sludge via mechanical aerators. The process can also be performed in open tanks, in which case oxygen is introduced to the sludge in minute bubbles with special diffusers. The bubbles dissolve before they reach the liquid surface. Because of the high cost of generating pure oxygen, it is cost-effective only when used in conjun ction with a pure oxygen activated sludge system. The principal advantage of the system is that it is relatively insensitive to changes in ambient temperatures when closed tanks are used because of the increased rate of biological activity and the exothermic nature of the process consequently, it is particularly applicable in cold weather...
Scientifically, the question of global warming was not a major issue at the time of the International Geophysical Year. Rather, the general understanding at the time was that the oceans would absorb almost all the excess carbon that humans may put in the atmosphere. Moreover, the war years had unusually cold weather, which made it less pertinent to discuss global warming. If anything was on the agenda, it was the perpetual question of the ice ages and the potential of a returning ice age on Earth. However, experiences of the vast impact of technology from using atom bombs had raised the legitimacy of ideas that people were able to affect the climate. There are examples of both scientists and politicians mentioning nuclear weapons and climate change as comparable threats to civilization. A popular belief was that fallout from the bombs could cause climate cooling.60 This theme resurfaced in the environmental debate in the early 1980s under the rubric of nuclear winter.61
Typical hydraulic loading rates on a single-stage filter range from 0.4 to 0.6 MG ac-d (0.37 to 0.56 m3 m2-d). If the SS in the influent to the filter will routinely exceed 50 mg L, the hydraulic loading rate should be reduced to 0.2 to 0.4 MG ac-d (0.19 to 0.37 m3 m2-d) to increase the filter run. In cold weather locations, the lower end of the range is recommended during winter operations to avoid the possible need for bed cleaning during the winter months.
At first, environmental concern was about global cooling. The 1960s were, climatologists now believe, the coldest decade of the 20th century, and several winters toward the end of the 1970s and beginning of the 1980s seemed to accelerate the trend. Numerous major magazines, such as Time and Newsweek, ran cover stories proclaiming the possibility of a new ice age, and the sudden rise in the price of home heating oil starting with the Arab Oil Embargo of 1973-74 only increased worries about the Earth growing colder. Staff at the Lamont-Doherty Observatory were asked to comment on global cooling a number of times, but none of their pronouncements on the subject came anywhere close to the importance given to the first major statement about global warming, which came in the summer of 1988.
A number of skeptics, however, continue to question the science and oppose policy changes regarding climate change. Some claim that climate change is not taking place at all and that warming is simply a natural cycle of change that is not due to human activity. If Hurricane Katrina forced some skeptics to rethink their assumptions about the severity of the threat, the unusually cold winter in 2006-07 was cited as further evidence of the uncertainty of the problem. A sizable portion of the U.S. population continues to believe that changing human behavior will have no effect on the process whatsoever. Instead, humans must simply adapt to changing circumstances.
Storage is generally not provided for SAT even where cold winters would limit operation of SR or OF systems (Reed et al., 1995). Proper thermal protection is needed for pumps, piping, and valves (Reed and Crites, 1984). Wastewater can continue to be land applied in SAT basins throughout subfreezing weather provided the soil profile does not freeze with moisture in it. Approaches that can be used to avoid critical ice formation include
The world's oceans also have a major effect on climate. Water has a higher specific heat than land, which means that it is more resistant to changes in temperature than is land. Thus, the fact that the majority of the earth is covered in water helps to keep temperatures stable worldwide. Moreover, the high specific heat of water affects local climates. Regions of land that are close to water tend to have warmer winters and cooler summers. Regions of land that are farther from water tend to have cold winters and hot summers.
For example, crops typically grown under certain agroclimatic conditions may face large increases in yield variability due to weather extremes during the growing season. Persistent extremes, such as drought, excessively hot summers, and excessively cold winters may alter the growing season, cause soil erosion, and land degradation. Other factors such as crop diseases and crop pests may be influenced by variable climatic conditions in a specific growing area.
The intensity of circumpolar vortices varies within a year, driven by seasonal air temperature gradient variations between low and high latitudes in the winter period in both hemispheres, atmospheric circulation intensifies, and in the 6-month summer period it weakens. The association between the state of polar vortices and air temperature is quite different in the climatic variability of warming and cooling epochs. In warming epochs, atmospheric pressure and geopotential values within the troposphere and the lower stratosphere decrease in the zone of polar vortices. This results in intensification of zonal flows in the atmosphere of mid-latitudes, which are apparent in indices of general atmospheric circulation, such as the North Atlantic Oscillation, the Arctic Oscillation, high-latitude zonation, and others in the Northern Hemisphere, and the South Polar Oscillation in the Antarctic. In cooling epochs, zonal flows become weaker (Gudkovich et al., 2008). It should be noted that the...
There is also the potential, however, for warming temperatures to reduce exposure and health impacts associated with cold winter temperatures, although this potential is projected to vary by location (CCSP, 2008a). For example, research has shown that regions with milder winters actually have higher mortality rates during cold weather than regions with colder winters (Curriero et al., 2002 Davis et al., 2004). Seasonal variations in death rates in the United States are well documented, with more deaths occurring during winter than during summer months (Curriero et al., 2002 Mackenbach et al., 1992). However, mortality rates are influenced by a range of factors other than temperature, including housing characteristics and personal behaviors, which have not been extensively studied in the context of future climate projections. Thus, determining whether warming temperatures could alter winter temperature mortality relationships is complex and requires understanding all of the factors...
In the Southern Ocean, wind-driven upwelling in and south of the Antarctic Circumpolar Current is an essential part of the MOC. The strength of Southern Hemisphere westerlies can affect the strength of this upwelling and may be the major control on the Southern Hemisphere MOC. Atmospheric warming would not easily disrupt the temperature, although it could affect the net upwelling transport (Toggweiler and Samuels, 1995). A weakened southern polar vortex would be associated with an equatorward shift of the storm track and a reduction in intensity of the cyclonic ocean circulations and upwelling. This might affect the ice edge (reduction in ice cover), which would exacerbate the warming and further weaken the polar vortex. However, because of the deep upwelling the impact of the oceanic portion of this feedback would not be as pronounced as if the upwelling had a much shallower source.
At the crop-ecosystem level, it is expected that crop yields will be enhanced in the northern regions of the former Soviet Union, Canada and Europe. The cereal-growing belts of North America might shift northwards by several hundred kilometres for every degree Celsius rise in temperature. The predicted yield increases in the higher latitude regions are primarily due to a lengthening of the growing season and the mitigation of negative cold weather effects on plant growth (Parry and Rosenzweig, 1993). Negative effects on crop and livestock productivity are expected in northern middle latitude countries like the USA, Western Europe and most of Canada's currently productive agricultural regions. This is due to a shortening of the growing period caused by increased temperatures and evapotranspiration rates (Tobey et al., 1992 see also Chapter 4).
In almost all climatic regions, lichens are among the first colonisers of exposed rocks and other substrata, except snow and ice. The ecological success of these symbiotic associations of fungi and green or blue-green algae in extremely cold, dry and nutrient-poor habitats of Antarctic is the result of their ability to tolerate long periods of desiccation and to uptake available water and essential elements over the entire thallus surface, by rapid passive processes. Cations are passively bound to anionic sites on the cell wall or outer surface of the plasma membrane, and may also enter and accumulate in mycobiont and photobiont cells through slower and more selective mechanisms (Bargagli and Mikhailova 2002). Besides gaseous and soluble elements and compounds, lichens can also trap airborne particles in the loose hyphal weft of the medulla (Garty et al. 1979). Lichens are perennial and, because of their slow growth rate, persistent atmospheric pollutants accumulate in the thalli to...
Compounding the mystery of initiation and maintenance of the above hot mode of the climate is the growing evidence that the earth has fallen into an extremely cold snowball-earth state, in which the entire planet became ice-covered. The most recent occurrence of a snowball state was in the Neo-Proterozoic, about 600 million years ago. The circumstances in which the Snowball can be triggered are hotly debated but almost certainly
In Europe, excess winter mortality is especially high in the United Kingdom (75,76). Indeed, relative excess winter mortality in the United Kingdom is approximately twice that in Scandinavian countries (72) and the Russian Federation (77). Social and behavioural adaptation to cold weather plays an important role in preventing winter deaths in high-latitude countries (78). The social or behavioural causes of the large excess mortality in winter in the United Kingdom are not well understood. Seasonal patterns of respiratory infections such as influenza are a significant cause of winter deaths, especially in epidemic years.
Although the occurrence of deep convection in the ocean is fairly easy to discern after the fact, it is a difficult process to observe in real time. This is partly because of the harsh wintertime conditions surrounding this phenomenon (high winds, cold temperatures, rough sea state, and often times ice), and also due to the fact that the lateral scales of the convective plumes are very small (Marshall and Schott 1999). It was not until March 1976 that deep convection was directly observed in the Labrador Sea using a shipboard conductivity temperature depth (CTD) profiler (Clarke and Gascard 1983). A typical storm that drives overturning in the western Labrador Sea is shown in Fig. 26.2. The storms generally follow the North Atlantic storm track past Newfoundland toward Iceland (Hoskins and Hodges 2002), and the cyclonic circulation draws bitterly cold air off of the Labrador landmass. Total ocean-to-atmosphere heat fluxes from the storms often exceed 500 W m-2, with the largest fluxes...
When scientists think about sea-level rise, therefore, they are contemplating glaciers, rather than icebergs. Glaciers are basically large masses of ice on land. They are created in areas where much more snow falls in the winter than can melt in the summer. Compressed under its own weight over many years, the snow eventually turns into ice.
Long-term trends in summer streamflow from the USGS gage at Thompsonville, Connecticut, shown in Figure 5-3, illustrate the interannual variability of discharge during the critical summer months. Seasonal flow conditions reflect the long, cold winters and the relatively short summers characteristic of New England. High flows are generally experienced in the spring (March-May), corresponding to large snow-melt events (Figure 5-4). Low flows occur during the summer months. In the past, flow regulation for hydropower production at Holyoke Dam (Massachusetts) periodically reduced flows in the Connecticut River to a minimum of near zero, but minimum re-
Seasonal cycles of planets are discussed in general terms in Chapter 7. The very low solar radiation received at the distant orbits of Uranus and Neptune leads to extremely cold outer atmospheres, particularly in the case of Neptune. These planets provide an opportunity to examine the novel features of an atmosphere driven by an exceedingly weak trickle of solar energy, supplemented by an equally feeble trickle of heat from the interior. Despite the weak thermal driving, Neptune has by far the strongest winds in the Solar system, as well as a variety of interesting meteorological features. We will not say much about planetary winds, but as in the case of the gas giants, a good understanding of the thermal structure is a prerequisite for any attack on the meteorology.
The climate of Antarctica embraces the most extreme cold conditions found on Earth. Antarctica is cold because the solar radiation is only 16 of that at equatorial regions, and also because of the high average surface elevation of the ice sheet, which in places exceeds 4,000 m. Temperatures as low as -89 C have been recorded at Vostok (Fig. 2.1), and -49 C at the South Pole. However, mean annual air temperatures increase nearer the coast where land is exposed, and in the northernmost areas (-25 C at Mt. Fleming at the head of Wright Dry Valley near the edge of the Polar Plateau, -20 C at Vanda Station in the Dry Valleys, -18 C at McMurdo Station on Ross Island, -15 C at Hallett Station). Further north, in coastal areas of East Antarctica, warmer climates are found (MacNamara 1973 Burton and Campbell 1980). At Davis Station in the Vestfold Hills, mean annual temperature is -10.2 C, while at Molodezhnaya and Casey (Fig. 2.1) similar temperatures to those at Davis Station are experienced.
The Arctic hosts a minor, but unique component of global biodiversity in that it contains endemic species and unique ecological processes and adaptations caused by a short growing season, a long and cold winter during which complete darkness reigns for a period which correlates with latitude (with equivalent periods of midnight sun each summer), and sea ice. Although the Arctic has relatively few species, the genetic diversity of many of these species is high, creating a mosaic of distinct populations and subspecies (Groombridge & Jenkins 2000 CAFF 2001). Knowledge of individual species and their distributions is fundamental in all ecological investigations. As biodiversity is lost across the globe (Wall et al. 2001), it becomes urgently important to document what species are present.
Today, for the Southern Hemisphere, the Earth is farthest from the Sun in June (winter) and closer to the Sun in December (summer) (Martin et al., 1997). As a consequence, seasonal differences in insolation are strong with warm summers and cold winters, and the seasonal shifts of the Intertropical Convergence Zone (ITCZ) are strong. Equatorward extents of cold advections under present-day conditions are shown in Fig. 11A. In contrast, at ca. 11,000 B.P., for the Southern Hemisphere, the Earth was closer to the Sun in June and farther from it in December, resulting in relatively colder summers, but relatively warmer winters than now and reduced seasonality. As a consequence, the continent was not warming as much then as during today's southern summer, and the ITCZ was probably located farther north than it is today. A weaker ITCZ, on the other hand, would have helped cold advections to penetrate further equatorwards in spring and autumn and possibly even in summer (Fig. 11B).
Impacts on human health due to global warming will come directly from increased heat stress and malnutrition. Additionally, vector-borne illnesses such as malaria will become more widespread in areas near the Equator, whereas deaths from extreme cold may decrease at high latitudes. Further, climate change has already and will further impact ecosystems leading to devastating species loss. The loss of these species affects the global economy through their loss as measured by their existence value and their potential uses in the pharmaceutical and ecotourism sector.
The gas concentration and average atmospheric lifetime must also be taken into account. The effect of methane, with a lifetime of about 12 years, is therefore less damaging than one might expect in view of its GWP. We must nevertheless bear in mind that the mechanisms involved in atmospheric circulation of these gases and their exchanges with the soil and the oceans are complex. This leads to uncertainties regarding the long-term behaviour of CO2 in the atmosphere and on the time required to return to equilibrium, in case of disturbance. The return to equilibrium occurs initially through absorption over several centuries of most of the CO2 in the atmosphere by the oceans and the biosphere, followed by a very slow mineralisation reaction during which CO2 is incorporated into carbonated rock, over a timescale of up to 100 000 years. This timescale extends well beyond our current forecast capabilities, especially since a new ice age is predicted to occur in 10 000 years. Whatever the...
For spring crops, climate warming will allow earlier planting or sowing than at present. Earlier planting in spring increases the length of the growing season thus earlier planting using long season cultivars will increase yield potential, if soil moisture is adequate and the risk of heat stress is low. Otherwise, earlier planting combined with a short-season cultivar would give the best assurance of avoiding heat and water stresses (Tubiello et al., 2000). For winter crops (i.e. cereals), a specific growth stage has to be reached before the onset of winter to ensure winter survival, thus they are often sown when temperatures approach the time when vernalisation is most effective (Harrison et al., 1995b). This may mean later sowings in northern Europe under a climatic warming (Harrison et al., 2000 Olesen et al., 2000). A specific study reported by Wolf (2000b) of the effectiveness of changes in potato crop management (i.e. variety, planting date, irrigation) showed that in northern...
The Norse farmers had developed an economy around the attributes of a landscape still dominated by glaciers and a climate controlled by the North Atlantic. First and foremost, they were livestock and dairy farmers, practicing a traditional husbandry that was common to Scandinavia. Through the cold winter, they stabled their animals indoors. In spring and summer, every patch of viable ground was used for pasture to sustain livestock through the growing season and to harvest for winter fodder. In the warmer seasons, they fished for cod and traveled up the western coast to hunt seals and caribou for food. They hunted walrus for fur and for their ivory tusks, their most important export to Iceland, Ireland, and Norway.
Northern wetlands and tundra ecosystems exist in the extremely cold desert climate of the Arctic. Yet, they often remain waterlogged during the summer, as the water balance is positive precipitation exceeds evaporation. This combination of factors affects the seasonality and rates of carbon exchange experienced by northern wetlands and tundra (Figure 15.9). Despite extreme cold temperatures during the winter, these ecosystems continue to respire (Vourlitis et al. 2000). Respiration occurs because microbes can remain active and decompose organic matter deep in the soil in unfrozen zones.
Ice cores are a sedimentary record like many others, but comprise snow and ice rather than terrigenous particles, with layers deposited sequentially, although unlike other records the layers thin with depth due to ice flow. They have the benefit that they record the atmosphere (including sampling precipitation, aerosol and trace gases) more directly than any other archive, without biological mediation. Highly resolved records, potentially datable by counting annual layers, are recovered at sites with high snow accumulation rates. The longest records extend back hundreds of thousands of years. However, at these sites annual layers cannot be resolved and far more difficult exercises are needed in order to derive a reliable age scale (e.g. Parrenin et al., 2007a). A particular strength of ice cores is that so many aspects of climate forcing and response are recorded in one core, while a weakness (less obvious for this book that concentrates on Antarctic climate) is that most ice core...
Accidents are not only much more likely to happen in the Arctic's supremely challenging natural environment, but are also far more difficult to respond to. Environmentalists point to all sorts of dangers, such as a severe shortage of natural light in winter, extreme cold and high winds that would make it extremely difficult to respond to an oil spill should it ever happen. 'The Arctic offers the highest level of ecological sensitivity and the lowest level of capacity to clean up after an accident', as James Leaton, an adviser to the WWF, has said. 'This combination makes it unacceptable to expose the Arctic to an unfettered scramble for oil.'18
Permafrost microorganisms also tend to be more halotolerant than organisms from the overlying active layer soil (Gilichinsky 2002a Steven et al. 2008a). Microbial survival in extremely cold environments is under the influence of ice formation and, consequently, little biologically available liquid water is present. Therefore, water activity is probably an important factor influencing microbial survival in permafrost (Gunde-Cimerman et al. 2003). In addition, during freezing and the binding of water in ice crystals, ions are expelled and concentrate in the remaining liquid phase (Price 2007). Thus, there may be a connection between halotoler-ance and microbial survival at extremely low temperatures.
Quite separate from the effects of temperature on wheat phenology are the effects of temperature extremes. Extreme cold may kill wheat, and late frost induces sterility (Russell and Wilson, 1994). Chilling temperatures (below 5 C) and hot temperatures (above 30 C) at anthesis can damage pollen formation, which in turn reduces grain set and can decrease yield (Dawson and Wardlaw, 1989 Tashiro and Wardlaw, 1990). There is a wide range of susceptibility to these effects among varieties. GEC will probably cause lower yields due to temperature extremes, simply by changing the frequency of temperature extremes over the short periods of particularly sensitive stages of plant development. Tolerance to such conditions will require breeding and selection of better adapted varieties (Acevedo, 1991).
South of the habitable continents is Antarctica, a land of unremitting snow and ice. The climate is too cold for the continent to host permanent settlements of humans. December averages minus 8 degrees F (minus 22 degrees C) and in January, minus 18 (minus 28 degrees C) . Precipitation, in the form of snow, falls in winter. Summer has clear skies and sunshine, but the sun is not warm enough at this latitude to melt the snow and ice. Instead, snow falls upon already existing piles of snow, compacting it into ice.
SERBIA AND MoNTENEGRo are two of six independent countries that formed after the disintegration of the former Yugoslavia in the early 1990s. These two countries neighbor each other in eastern Europe and cover geographic regions with diverse climates. Serbia is landlocked and geographically positioned in the region of mild continental climate, whereas Montenegro also has a coastal region with a Mediterranean climate. Both countries have significant local climate variations resulting from local atmospheric circulations, as well as mountainous and hilly terrain away from Montenegro's Adriatic coast. In general, the subalpine climate with short cold winters and relatively hot summers is typical for elevations of from 2,000 ft. (600 m.) to 4,000 ft. (1,200 m.), and the Alpine climate with long and snowy winters and short warm summers is characteristic for elevations above 4,000 ft. (1,200 m.). The capital of Serbia is Belgrade. Belgrade has a moderate continental climate that has hot...
Many regions of the world, such as the Indian Subcontinent, the Andes region of South America, Kazakhstan, California, and the American High Plains, rely on melt water from glaciers and heavy winter snows to feed streams and rivers that provide water for irrigation. These high altitude water sources have traditionally been viewed as renewable resources that can be depended upon to provide moisture during the growing season and are then replenished by snow falls during the frigid winters. However, rising temperatures have caused glaciers to shrink or disappear and have been linked to reduced snow pack at high altitudes.
This history clearly shows us that Antarctica and similar ice sheets have had the potential to raise global sea level rapidly and to cause significant changes in the Earth System, but we should also ask if that potential still exists today We live in an interglacial period, but despite the persistence of interglacial conditions for more than 10kyr the Earth appears to be only partially deglaciated. There are still glaciers and ice caps on every continent, and the vast ice sheets covering Greenland and Antarctica are probably still extensive compared with previous interglacials. This relative abundance of glaciers, compared with previous interglacials, results from a modern climate that is cooler than that at the height of two of the last three interglacials (Petit et al., 1999). However, these slightly cooler conditions may not continue despite the scare stories prevalent in the media during the 1970s that predicted an imminent descent into a new glacial period ('The New Ice Age'),...
Oxygen and nutrients (nitrogen and phosphorus) (e.g. Metcalf & Eddy, 2002). The microorganisms convert the soluble organic compounds to carbon dioxide and cellular material, i.e. new biomass. Oxygen is obtained from applied air which also maintains adequate mixing. The bioreactor effluent is settled to separate biological sludge and a portion of the sludge is recycled the excess is sent for further treatment such as dewatering. Activated sludge systems utilised in the food processing industry are the extended aeration types that is, they combine long aeration times with low applied organic loadings. Typical food microorganisms (F M) ratios are lower than 0.1 kg COD kg mixed liquor volatile suspended solids (MLVSS) per day while sludge age (solid retention time, SRT) should be maintained at values greater than 20 days. This practice allows for a relatively low production of waste activated sludge, typically
12.4.3 .Without adaptive measures, risks to health due to more frequent heatwaves, particularly in central and southern Europe, and flooding, and greater exposure to vector- and food-borne diseases are anticipated to increase 188.8.131.52, 12.6.1 . Some impacts may be positive, as in reduced risk of extreme cold events because of increasing winter temperatures. However, on balance, health risks are very likely to increase 12.4.11 .
The first step in the formation of the Antarctic ozone hole is the formation of the polar vortex 187J. During the winter the Antarctic region experiences 24 h of darkness every day. There is no heating by absorption of solar ultraviolet radiation during this time. Emission of thermal radiation, however, continues, causing the Antarctic lower stratosphere to cool (Figure 7.4). The resulting cold polar temperatures coupled with relatively warm temperatures in the mid-latitudes causes a strong pressure gradient to form between the polar and mid-latitude regions. Because of the coriolis force, this north-south pressure gradient creates a zonal (east- west) wind.
Under elevated CO2 have a lower leaf N concentration, due to the increase in carbohydrate production that 'dilutes' the protein content of the leaf (Lambers, 1993). This increased carbohydrate supply in plants exposed to elevated CO2 tends to increase the concentration of secondary compounds in leaves. Such compounds play an important role in distinct ecological functions, including allelopathy and the deterrence of herbivores (Baas, 1989 Dicke and Sabelis, 1989 Lambers, 1993). These changes in plant composition alter interactions between plant and herbivory (see Chapter 16, this volume). Prolonged development, increased food consumption, decreased food processing efficiency and general growth reduction are some of the typical responses of insects to reduced leaf N concentration (Roth and Lindroth, 1995). Hence, changes in plant composition in response to rising CO2 may influence the feeding habits and spread of insect populations. This aspect was investigated in the potato FACE...
It is generally expected that with climate warming in mid- to high-latitude regions, insect pests become more abundant. The main effect of climate warming in the temperate zone is believed to be a change in winter survival, while in the northern latitude shifts in phenology in terms of growth and reproduction, may be of prime importance (Bale et al. 2002). Shifts in climate are also likely to affect the geographical distribution of insects. Species-specific responses of pests to increasing O3 concentrations were observed (see Fuhrer 2003).
New Hampshire has cool summers and long cold winters, though weather can have extreme variations. New England weather and climate is influenced by latitude (warm, moist air from the south and cold, dry air to the north), coastal orientation (position within the zone of the westerlies), and elevation changes. In winter, these waters remain warm relative to land areas, thereby influencing snow-rain boundaries, which are difficult for forecasters to predict. The highest temperature recorded in the state was 106 degrees F (41 degrees C) on July 4, 1911, and the lowest temperature recorded
Glaciers form mainly by the accumulation and compaction of snow and are deformed by flow under the influence of gravity. When snow falls it is very porous, and with time the pore spaces close by precipitation and compaction. When snow first falls, it has a density of about one-tenth that of ice after a year or more, the density is transitional between snow and ice, and it is called firn. After several years, the ice has a density of 0.9 gm cm3, and it flows under the force of gravity. At this point, glaciers are considered to be metamorphic rocks, composed of the mineral ice.
In its most basic form, FC has been employed since as far back as the Middle Ages. Beer or wine in wooden barrels would be exposed to the cold winter nights, causing water to freeze along the barrel walls and leaving a concentrated product in the middle of the ice shell.
Terrestrial insects and plants freeze solid for the winter. As autumn approaches, these organisms prepare by dehydrating and synthesizing antifreezes and biochem-icals that reduce the cellular damage caused by freezing. Even the frogs that overwinter frozen (e.g., in the Arctic, the wood frog Rana sylvatica see Amphibians) go through similar physiological preparations. Body antifreezes are also found in fish that live in water at subzero temperatures in the Antarctic. Insects may overwinter at various stages of development. Mosquitoes overwinter as eggs, various butterflies and moths as caterpillars, and bumblebees as adult, mated queens. Generally, they seek some sort of shelter prior to entering the overwintering state. The shelter selected by woolly bear caterpillars is a place that is sheltered from high wind, but where snow will not become deep. Thus, when the early summer sun melts the snow, it soon warms the caterpillar. Most plants spend the winter with leaves intact, some...
An example of the use of proxy data would be conducting a North American winter snow survey by searching North American garages for snow shovels in the summer. In regions where snow shovels are common in garages, a researcher might reasonably interpret cold winter temperatures and the presence of snow. The shovels, though not actually snow, are a proxy for the occurrence of winter snow. In regions without snow shovels, winter temperatures are either warmer with no snow, or snow is removed in a different way. Because proxy data may be definitive in one sense, but ambiguous in another, using them to decipher the nature of
A similar observation of record low total column ozone over Lauder, New Zealand, down to 222 DU compared to the 1985-1996 average of 340 DU was reported by Brinksma et al. (f 998). They attributed the low ozone in part to a portion of the Antarctic polar vortex passing over this location at altitudes of 25-35 km and in part to injection at lower altitudes ( 22 km) of ozone-poor subtropical air.
Apart from some exceptional circumstances, the thermal inertia of a solid surface has little effect on the seasonal cycle, though it can substantially moderate the diurnal cycle. This can be seen easily through the evaluation of tauD in a few typical cases. First we consider the case of Antarctic or Arctic ice-covered regions. The flux coefficient based on a linear OLR fit in the temperature range 240K to 270K is b 2.16W (m2K). Using the heat capacity and thermal diffusivity for water ice, given in Table 7.1, we find tauD 11Earthdays. At latitudes somewhat away from the poles, the diurnal cycle of insolation becomes significant, particularly during the equinoxes. Since the time scale for the surface is shorter than that for the atmosphere, it would be more appropriate to use surface flux coefficients than OLR in analyzing the terrestrial diurnal cycle. As noted in Chapter 6, the turbulent heat transfer is strongly inhibited at night-time, when the boundary layer is statically stable....
In temperate latitudes, the length of the growing season will increase, and with it the fraction of the year when forests and grasslands are green. On average, the warm season will expand by about a month at either end. Future Aprils will be like modern Mays, and future Novembers like modern Octobers. Again, such a shift is now under way the growing season measured both by satellites and by ground observations has expanded by about a week in the spring and by half a week in the autumn over the last two decades. Part of this change probably reflects the greater availability of atmospheric CO2 in giving plants a fertilizer boost, but part of it is also due to the warming in recent decades. Another significant change at temperate latitudes will be a reduced number of bitterly cold outbreaks of polar air masses in winter.
The importance of frozen ground for infiltration and groundwater recharge is significant in zones with rock glaciers. These occur in the Dischma at altitudes above 2400 m and in the Solk valleys above 2250 m. Permafrost is another key factor combining local hydrology, meteorology and geomorphology in high alpine valleys and slopes (Schrott 1998). This is well documented for the Dischma (Haeberli & Beniston 1998). At the end of the winter, the distribution of permafrost is as important as temporarily frozen ground. The latter is dominant during cold winters with shallow snow cover and wind drift. Under such conditions, water from snowmelt and first rain will be transported close to the surface as long as subsurface sediments and soils are frozen.
The dominant pattern of atmospheric circulation variability over the North Atlantic is known as the North Atlantic Oscillation (NAO), and its wintertime index is shown in Figure 7.3.2a (updated from Hurrell, 1995a). The NAO, which is linked to changes in the surface westerlies across the Atlantic onto Europe, refers to a meridional oscillation in atmospheric mass with centres of action near Iceland and over the subtropical Atlantic from the Azores across the Iberian Peninsula. Positive values of the NAO index indicate stronger than average westerlies over the middle latitudes with low-pressure anomalies in the Icelandic region and high-pressure anomalies across the subtropical Atlantic. This phase of the oscillation is also associated with cold winters over the northwest Atlantic and warm winters over Europe, as well as wet conditions from Iceland through Scandinavia and winter dry conditions over southern Europe (Hurrell, 1995a).
The natural annual period of effective treatment at a contaminated site in the Arctic is 2-3 months, and 1-2 months in coastal Antarctica. In sub-polar regions, the treatment season varies up to 6 months. Generally, cold weather and freezing and frozen ground conditions dictate the treatment season and efficacy. However, engineered remediation can enhance conditions within the contaminant zone and extend the treatment season by a couple of months. Location may limit treatment options as a function of cost and manpower needs restricted site access limits treatment options.